Drill head



2 Sheets-Sheet l attorney June 6, 1939. J. A. ANDERSEN DRILL HEAD Filed July 25', 193'? June 6, 1939. J. A. ANDERSEN 2,161,000

DRILL HEAD Filed July 2;, 1957 2 Sheets-She d? nhmeslhfinderaz t Snventor Patented June 6, 1939 UNITED sriATEs PATENT OFFICE 4 Claims.

My present invention relates to an improved drill head of the rotary, multiple cutter, motor or power operated type for use in earth boring, and the invention is involved in the structure of the drill-head, bit, or augur of a machine tool, of this type. The invention is embodied in a drill-head having a central augur which includes a spiral arrangement of drill-sections, in combination with one or more annular cutters arranged concentrically of the augur and exterior of the augur, whereby a comparatively large bore may be drilled in the earth and the debris from the drilled bore may with facility be withdrawn to insure smooth operation of the drill head.

While the drill head or my invention is applicable for various uses and purposes, it is especially adapted for drilling cylindrical passages through coal formations in mines, as, for instance, for boring a passage from one level in the mine to another level, to provide a chute through which coal may be transferred from an upper level to a lower level or into a waiting car at the lower level.

By the use of my improved drill-head such chutes or tunnels may be constructed with facility and with comparatively slight expense, and due to the cylindrical structure of the walls fashioned by the drill-head, the walls are of such strength and durability as to eliminate the necessity for lining, or bracing, the walls with timbers.

In carrying out my invention the central augur of the drill-head is stepped, and the larger, multiple, concentric cutters or wall-breakers are also stepped as to size and location, with the result that successive cylindrical walls are bored or drilled during the drilling operation, and these cylindrical walls are successively broken down or cut away as the drill-head advances through the coal in a vein, and the ultimate size of the bore is the size of the maximum cutter or drillsection.

My invention consists in certain novel combinations and arrangements in the drill head in'- volving the central stepped augur and the multiple exterior stepped cutters of annular formation, together with means for adjusting the multiple cutters, as will hereinafter be more fully pointed out and claimed. In the accompanying drawings I have illustrated one complete example of the physical embodiment of my invention wherein the parts are combined and arranged according to one mode I have thus far devised for the practical application of the principles of my invention.

Figure 1 is a view in elevation of my improved drill-head showing it in use as drilling a bore or passage through coal or other fragile material, and equipped with auxiliary means for adjusting the position of the wedge-shaped breakers or cutters of the annular, stepped, drill sections.

Figure 2 is a detail perspective view of one of the wedge-shaped cutters detached from an annular section or cutter-holder.

Figure 3 is a detail perspective view of one of the rotary concentric cutter-holders or drill sections, detached from the drill-head of Figure 4.

Figure 4 is an enlarged detail of the drill-head, with parts in section for convenience of illustration, and omitting the adjusting means of Figure 1.

Figure 5 is an enlarged, sectional detail view at line 5-5 of Figure 4.

Figure 6 is a perspective view of one of the wedge-cutters, or of one of the reaming cutters, as used on the exterior of the forward augur section of the drill-head.

In Figure 1 I have designated at V a portion of a vein of coal, (or of other fragile material) and the letter P indicates the passage, bore, or 25 chute, that is usually drilled upwardly through the coal vein, at either an acute angle or at an obtuse angle, and under these conditions the debris from the drill head falls by gravity away from the drill-head as the latter advances, thus insuring clearance for the drill-head as it rotates or revolves under suitable power.

The drill-head includes a drill-bar or shank l which at its rear end is connected to mechanism for imparting rotary motion thereto, and at its 35 forward end 2 the shaft or bar is angular in cross section to receive the drill-head sections that are I provided with complementary angular hubsockets.

The central, stepped augur is here shown as made up of three sections 3, l, and 5, and an end bit 6 which has a threaded stem 6' shown by dotted lines in Figure 4 and screwed into the socketed and threaded end of the drill rod or shaft I. The three sections 3, l, and 5 are each provided with angular bores I so that the sections may be slipped over the angular end of the shaft or rod, with the largest section 3 at the rear, the smallest section 5 at the forward end of the drill head, and the intermediate section I in position as shown. The augur sections, thus increase in size from the front to the rear, and the spiral formation of the three sections produces an increase in the diameter of the bore as the drill-head advances. The debris is conveyed to augur-section, and these the rear as the augur advances, and the bore is thus cleared during the operation of the drill head.

On the forward augur-section 5 I may employ reaming cutters as 8 on the exterior turns of the exterior or lateral cutters back of the cutter-head't assist in cutting away the material of the first or smallest of the stepped bores fashioned by the drill-head.

In addition to the central augur I employ an nular cutters that rotate with the augur of the drill-head, and these annular cutters which are arranged concentrically of the central augur cut concentric, stepped, cylindrical walls in the coal, which walls are easily broken down as the drillhead advances, and the debris therefrom is passed backward through the bore and readily disposed of. Three of these annular cutters are indicated as 9' 9a and 9b in Figure 1 and 9 in Figure 4. These cutters decrease in size or diameter in the order named and the two forward cutters 9b and 9a are interposed between sections of the augur. In Figure 1 the lowest and largest cutter 9' is provided with an auxiliary breaker as will be described, while in Figure 4, the lowest and largest cutter is designated as 9. Each annular cutter. as best indicated in Figure 3,comprises a circular spider frame or hclder having a central angular socket II] at its hub, which is slipped over the angular portion 2 of the drill shaft or bar from its outer end and thus secured to turn with the shaft or rod. Each spider frame or holder is provided with two or more arms II, II, and each holder is equipped with wedge shaped cutters as I2, I3, and I4 that are spaced at successively greater distances from the drill-shaft I from front to rear of the drill head. These wedge-shaped cutters are preferably renewable and replaceable and they are provided with screws l5 that are threaded into sockets I6 in the ends of the holder arms II. Thus the set of three annular cutters, increasing in diameter from the front cutters It to the rear cutters I2, cut annular grooves which form cylindrical walls in the coal, and these cylindrical walls concentrically arranged have successively increasing diameters. These comparatively thin cylindrical walls are readily broken down as the drill-head advances, due to the conjoint use of the stepped augur and the stepped annular drills or cutters, and the ultimate bore of maximum size and cylindrical shape is smooth and solid for maintaining the walls of the passage or chute in its future use.

As auxiliary means for breaking down the concentric, annular, stepped walls fashioned by the augur and annular cutters, I may employ adjustable breakers or cutters I! and I8 that are mounted in the cutter holders or spider frames, and in position to frictionally engage 'the exterior face of a cylindrical wall. These cutters or breakers rotate or revolve with the drill-head, the cutter I! being mounted at the end of a rod l9 which extends parallel with the drill shaft I and may be turned or adjusted through the use of a, hand wheel 20 mounted at its rear end. The rod I9 is journaled to turn in bearing brackets 2|, 2| rigid with the drill shaft, and this rod, which passes through the cutter holder or spider frame 9', is supported in a sleeve 22 rigid with the holder or fr me 9a, and the cutter or breaker 'adjust the cutter or I! is mounted on the rod in this sleeve, pro jecting forward of the holder.

The cutter or breaker I8 is mounted on the end of a stem 23 that passes through a sleeve 22 of the spider frame 9', and this stem and its cutter may be turned or adjusted about its axis through a power transmission device 24. Thus, as the rod I9 is turned by hand wheel 20 to breaker l1, the cutter or breaker I8 is also turned or adjusted for frictional contact with a cylindrical wall. In this manner the auxiliary cutters or breakers I1 and I8 assist in breaking down the cylindrical walls that are fashioned by the augur and annular cutters, so that the bore or passage P may be fashioned by the rotary drill-head without subjecting the various parts of the drill-head to excessive strains. The multiple operations of the cutters and of the augur distribute the drilling or boring action over a comparatively extensive area, and the formation of the annular grooves and cylindrical walls permit the stepped augur and stepped cutters to readily break down the cut material, leaving the cylindrical bore or passage P with a clean cut surface without danger of crumbling.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination in a rotary drill-head with a drill-shaft angular in cross section and an end drill-bit rigid with the shaft, of a pair of helical augur-sections having complementary bores and mounted on the shaft, a cutter holder having an angular hub mounted on the shaft and interposed between said augur-sections, and an annular series of cutters mounted on said holder concentric with and exterior of said augur-sections.

2.. The combination in a rotary drill-head with a drill shaft angular in cross section and an endbit detachably mounted on the shaft, of a pair of helical augur-sections having complementary bore: and mounted on the shaft, a cutter holder com; ising a spider-frame having an angular hub socket mounted on the shaft between said sections, a plurality of arms projecting forward from said spider frame, and an annular series of cutters mounted on said arms concentric with and exterior of the augur-sections.

3. The combination in a rotary drill-head with a central spiral auger comprising three augersections, and a supporting shaft rigid with said sections, of three cutter-holders mounted on said shaft and located at the rear ends of said sections, cutter-arms rigid with said holders, and replaceable wedge-shaped cutters mounted on said arms concentric with and exterior of said auger-sections.

4. The combination in a rotary drill-head with a central spiral auger comprising three augersections, and a supporting shaft rigid with said sections, of three cutter holders mounted on said shaft and located at the rear ends of said sections, cutter arms rigid with said holders, replaceable wedge-shaped cutters mounted at the ends of said arms concentric with and exterior of said auger sections, auxiliary cutters mounted in said holders, and means for adjusting said auxiliary cutters, for the purpose described.

JAMES A. ANDERSEN. 

